1. Field of the Disclosure
The present invention relates to a touch panel and a manufacturing method thereof, and particularly to an added-on touch panel and a manufacturing method thereof.
2. Description of Related Art
In recent years, digital information and wireless mobile communication technology are dramatically developed. To meet current demands on portable, compact and to be user-friendly, most of information technology (IT) products such as mobile phones, handheld PC, personal digital assistances (PDA), smart phones or the like are now using a touch panel as an input device instead of a conventional input device such as a keyboard or a mouse. Besides the convenience, and also because of the intuitive operation, the touch inputting technology becomes a popularized human-machine interface and multi-media interactions, and thus is becoming greatly concerned and developed.
Based on different sensing principles, touch panels can be generally categorized into resistive touch panels, capacitive touch panels, optical touch panels, acoustic-wave touch panels, electromagnetic touch panels and the like, wherein because having the advantages of fast response speed, favorable reliability and durability, the capacitive touch panels have been extensively applied to electronic devices. According to different structures and manufacturing methods, the capacitive touch panels can be further classified into on-cell types, in-cell types and added-on types. For on-cell type touch panels and in-cell type touch panels, touch functions are directly integrated into manufacturing processes of the panels, wherein sensing series are disposed on the outer surface or the inner surface of the display panel. The added-on touch panels usually have sensing series fabricated on another substrate, and the substrate on which the sensing series have been formed is then attached to the outer surface of the display panel.
The conventional added-on touch panels include a substrate, touch-sensing circuit and fan-out traces. The substrate has a touch-sensing region and a peripheral region surrounding the touch-sensing region, so that the touch-sensing circuit is located on the touch-sensing region of the substrate and the fan-out traces are located on the peripheral region of the substrate. One end of the fan-out trace is electrically connected to the touch-sensing circuit, and another end of the fan-out trace is electrically connected to an integrated circuit (IC) attaching area located on the peripheral region of the substrate. When the integrated circuit is attached to the substrate, the integrated circuit is electrically connected to the touch-sensing circuit through the fan-out traces.
However, disposing a plurality of fan-out traces on the peripheral region of the substrate requires configuring specific gaps among the fan-out traces. If line width and the space between the lines of the fan-out trace are too large, the area of peripheral region would be increased and it may not comply with the demand of slim border design. However, if the line width and the space between the lines of the fan-out trace are too small, then the resistance of the fan-out trace would be increased and the sensitivity of the touch panel may be affected. For instance, when both the line width and the space are 30 μm, the resistance of the fan-out trace is high enough to affect the sensitivity of the touch panel.